BackflowNear Test-Due Reminder

Approved backflow testers in Frederick, MD

27 backflow testing businesses work within 25 miles of Frederick, 3 of them based in town. 5 have testers on Maryland's roster and 22 are on the approved tester list of 5 water utilities.

27 businesses within 25 miles

Backflow testing companies near Frederick

What the badges mean
✓ MD Certified Backflow Tester Verified
A state roster lists at least one certified tester at this business, with a current certificate. The state sets the exam and renewal.
✓ MD Utility-Approved Tester Verified On the city list
The company is on a water utility's own approved list (the second badge names the list). That is the utility's approval, not a state license, and it counts for that utility.
3 certified testers
How many certified testers the roster lists at this business.
★ 4.8 (25 reviews)
The Google rating, shown as Google reports it. It does not change the order.

Order is by our quality score, never by payment. How we verify listings.

Are you a backflow testing company near Frederick? One sponsor per county, clearly labelled. Sponsor this county

Ben Lewis Plumbing

90/100
✓ MD Utility-Approved Tester Verified ★ 2.6 (38 reviews) On Anne Arundel County list Backflow Testing

23407 Frederick Rd, Clarksburg, MD 20871 · 12 mi from Frederick

Call (301) 428-3900 Details Website
Verified Oct 2026 · Unclaimed listing

O'Conor Plumbing Services, LLC

90/100
✓ MD Utility-Approved Tester Verified ★ 4.5 (231 reviews) On DC Water listOn WSSC Water listOn Anne Arundel County listOn City of Rockville list Backflow Testing

19301 Mateny Hill Rd, Germantown, MD 20874 · 17 mi from Frederick

Call (301) 540-5050 Details Website
Verified Oct 2026 · Unclaimed listing

The Drain Guys

90/100
✓ MD Utility-Approved Tester Verified ★ 4.7 (186 reviews) On City of Rockville list Backflow Testing

8041 Cessna Ave Ste 100, Gaithersburg, MD 20879 · 20 mi from Frederick

Call (301) 867-7632 Details Website
Verified Oct 2026 · Unclaimed listing

Mallick Plumbing & Heating, Inc

90/100
✓ MD Utility-Approved Tester Verified ★ 4.9 (2436 reviews) On DC Water listOn WSSC Water listOn City of Rockville list Backflow Testing

7620 Rickenbacker Dr Ste L, Gaithersburg, MD 20879 · 20 mi from Frederick

Call (301) 840-5861 Details Website
Verified Oct 2026 · Unclaimed listing

Delmar Plumbing, LLC

80/100
✓ MD Utility-Approved Tester Verified ★ 3.3 (16 reviews) On DC Water list Backflow Testing

2 Hilton Ct, Gaithersburg, MD 20882 · 16 mi from Frederick

Call (301) 774-2355 Details
Verified Oct 2026 · Unclaimed listing

Harvey W. Hottel

90/100
✓ MD Utility-Approved Tester Verified ★ 4.1 (48 reviews) On DC Water list Backflow Testing

18900 Woodfield Rd, Gaithersburg, MD 20879 · 20 mi from Frederick

Call (301) 461-0622 Details Website
Verified Oct 2026 · Unclaimed listing

James A Wheat & Sons

90/100
✓ MD Utility-Approved Tester Verified ★ 4.8 (1300 reviews) On DC Water listOn WSSC Water listOn City of Rockville list Backflow Testing

7834 Beechcraft Ave, Gaithersburg, MD 20879 · 20 mi from Frederick

Call (301) 670-1944 Details Website
Verified Oct 2026 · Unclaimed listing

Reliable Plumbing

90/100
✓ MD Utility-Approved Tester Verified ★ 1 (3 reviews) On City of Rockville list Backflow Testing

21509 Ripplemead Dr, Gaithersburg, MD 20882 · 21 mi from Frederick

Call (301) 948-1991 Details Website
Verified Oct 2026 · Unclaimed listing

MPM Plumbing

90/100
✓ MD Utility-Approved Tester Verified ★ 5 (9 reviews) On City of Rockville list Backflow Testing

5 Mineral Springs Ct, Gaithersburg, MD 20877 · 21 mi from Frederick

Call (301) 208-8362 Details Website
Verified Oct 2026 · Unclaimed listing

Backflow Technology, LLC

90/100
✓ VA Utility-Approved Tester Verified ★ 4.8 (8 reviews) On DC Water listOn City of Rockville listOn Loudoun Water list Backflow Testing

20700 Loudoun County Pkwy #192, Ashburn, VA 20147 · 24 mi from Frederick

Call (703) 450-5898 Details Website
Verified Oct 2026 · Unclaimed listing

Shary's Plumbing

90/100
✓ MD Utility-Approved Tester Verified ★ 4 (29 reviews) On DC Water listOn WSSC Water listOn City of Rockville list Backflow Testing

3401 Kemptown Church Rd, Monrovia, MD 21770 · 25 mi from Frederick

Call (301) 229-6695 Details Website
Verified Oct 2026 · Unclaimed listing

Robert A. Tull, Inc.

80/100
✓ MD Certified Backflow Tester Verified ★ 2.8 (31 reviews) On WSSC Water listOn City of Rockville list Backflow Testing

7820 Airpark Rd, Gaithersburg, MD 20879 · 20 mi from Frederick

Call (301) 948-2490 Details
Verified Oct 2026 · Unclaimed listing

Price reports

What a backflow test costs in Frederick

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Published prices nationwide

$29.99 to $100 per assembly

Based on 14 published prices · Read Oct 2026 Prices testing businesses list on their own websites, from our cost guide. Listed prices, not what people paid.

Every published price, with its source: what a backflow test costs.

Failed test? Published repair, rebuild and replacement prices: what a backflow repair or replacement costs.

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Backflow testing questions in Frederick

Where are the backflow testing businesses listed for Frederick based?

27 backflow testing businesses are listed within 25 miles of Frederick. 3 are based in Frederick itself, 4 more within 15 miles and 20 further out, up to 25 miles away. Other towns with more than one listing: Gaithersburg (11), Rockville (3) and Monrovia (2). The closest is All Around Plumbing Inc., 2 miles from Frederick.

Which tester lists are the businesses near Frederick on?

5 have testers on Maryland's roster and 22 are on the approved tester list of 5 water utilities.

How many of the backflow testing businesses near Frederick have Google reviews?

24 of the 27 listed for Frederick have 3 or more Google reviews. Mallick Plumbing & Heating, Inc has the most reviews, 2,436, with an average of 4.9 stars, as Google showed them at our last check.

Approved list: WSSC Water plumbing firms providing cross-connection related services, WSSC Water.

Approved list: Backflow Prevention Assembly Service Providers, DC Water.

Approved list: Anne Arundel County accepted plumbing companies providing backflow related services, Anne Arundel County Department of Public Works.

Approved list: City of Rockville certified backflow prevention testers, City of Rockville Department of Public Works.

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